S52 swap - Car dies with MAF plugged in

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Hi all, I'm desperately trying to finish my project before the weather turns. I chopped up a running/driving '97 E36 M3 to stuff into my '87 325 along with RHD's ITB kit. Everything is pretty much wrapped up. It starts and idles well but only with the MAF unplugged. I tried 3 different MAFs before figuring out there is no 12v power going into pin 1 on the connector. At the x20 plug, I have continuity to pins 15, 18, and 23.


The ECU is fresh from Kassel with EWS, SAP and rear O2 delete. I'm guessing there's a short to ground in the engine loom. Anything else I can check before I rip the engine harness apart?

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Pin 3 of the MAF connector has 12v on a red/white wire. according to the write-up in link below, this should be on pin 1. Tempted to cross the wires but this seems ridiculous to do to what was a running driving setup when I started. Would I then do the same with 2 and 4? What might I have crossed up elsewhere?

https://www.bimmerforums.co.uk/threa...esting.335401/

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So... chasing continuity to the DME shows 1 rings pins 4, 28, 32 and 34 at the dme, 2 rings 8, 3 rings 7... All of this matches the wiring diagrams.

At this point, I'm assuming that sensor testing guide was incorrect on some level. Not even sure if the MAF is my issue anymore.